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United States Patent |
6,179,020
|
Hutchinson
|
January 30, 2001
|
Fluid level controlled automatic shutoff valve
Abstract
The present fluid level controlled automatic shutoff valve is comprised of
a tubular housing with an axial bore which has an upstream closure, a
downstream opening, and an annular piston seat at the downstream opening.
A movable piston is positioned in the bore, and biased to a retracted
position by a tension spring connected between the piston and the closure
of the bore. A plurality of channels on the wall of the housing extend
between an upstream end of the housing and the bore. The channels
terminate in venturis downstream of the piston in the retracted position.
The shutoff valve is positioned in a fluid dispensing device. When
pressurized fluid is delivered through the dispensing device, the fluid is
directed through the channels and out the venturis at high speed and low
pressure. Before the fluid level in a container being filled reaches an
open lower end of the dispensing device, the pressures between the
upstream and downstream ends of the piston are balanced by air flowing
into downstream opening of the bore from the open lower end of the
dispensing device. When the fluid level reaches the open lower end of the
dispensing device, the air flow is cut off, and the low pressure fluid
from the venturis pulls the piston into the seat at the downstream opening
of the bore. Fluid flow is shut off.
Inventors:
|
Hutchinson; Peter (2150 Upper Ridge Rd., Green Lane, PA 18054)
|
Appl. No.:
|
482412 |
Filed:
|
January 13, 2000 |
Current U.S. Class: |
141/206; 137/484.2; 137/500; 141/198 |
Intern'l Class: |
B65B 001/04 |
Field of Search: |
137/484.2,484.6,500
141/95,198,206,214,215,392
|
References Cited
Attorney, Agent or Firm: Lo; Jack
Claims
I claim:
1. A shutoff valve, comprising:
a tubular housing with an axial bore, an upstream end, and a downstream
end, said bore including an upstream closure and a downstream opening;
a venturi connecting an outer wall of said housing and said bore, said
venturi generally directed at said downstream opening of said bore;
a movable piston positioned in said bore, said piston including an upstream
end and a downstream end, said piston movable between a retracted position
upstream of said venturi and away from said downstream opening of said
bore, and an extended position downstream of said venturi and against said
downstream opening of said bore; and
a spring biasing said piston to said retracted position.
2. A shutoff valve, comprising:
a tubular housing with an axial bore, an upstream end, and a downstream
end, said bore including an upstream closure and a downstream opening;
a channel extending along an outer wall of said housing from said upstream
end of said housing;
a venturi connecting said channel and said bore, said venturi generally
directed at said downstream opening of said bore;
a movable piston positioned in said bore, said piston including an upstream
end and a downstream end, said piston movable between a retracted position
upstream of said venturi and away from said downstream opening of said
bore, and an extended position downstream of said venturi and against said
downstream opening of said bore; and
a spring biasing said piston to said retracted position.
3. A shutoff valve, comprising:
a tubular housing with an axial bore, an upstream end, and a downstream
end, said bore including an upstream closure, a downstream opening, and an
annular piston seat at said downstream opening;
a plurality of channels extending along an outer wall of said housing from
said upstream end of said housing;
a plurality of venturis connecting said channels and said bore, said
venturis generally directed at said downstream opening of said bore;
a movable piston positioned in said bore, said piston including an upstream
end and a downstream end, said piston movable between a retracted position
upstream of said venturis and away from said piston seat, and an extended
position downstream of said venturis and against said piston seat;
a tension spring connected between said piston and said upstream closure of
said bore, said spring biasing said piston to said retracted position; and
a drain hole extending between said upstream end and said downstream end of
said piston.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to automatic shutoff valves controlled by
the fluid level in a container.
2. Prior Art
When filling a container with a fluid dispensing device, such as a water
gun, an operator must closely monitor the fluid level. The valve on the
dispensing device, such as a trigger, must be manually kept open for a
prolonged period, and manually closed when the desired fluid level is
reached. This method is time consuming when filling a large container, and
tedious when repeatedly filling multiple containers.
Numerous automatic shutoff valves are known for shutting off flow when a
predetermined fluid level is reached in a container being filled. They are
particularly useful for automatically filling the cells of a lead-acid
battery to a predetermined level. However, they are relatively complicated
and expensive to produce.
A simpler automatic shutoff valve is shown in U.S. Pat. No. 4,556,093 to
Jones, and is arranged inside a dispensing device. It includes a movable
tube connected to the downstream end of a constricted venturi, which
directs a jet of fluid along the inside wall of the tube. A ball
positioned upstream of the venturi is connected to the movable tube by a
wire. The ball is kept away from the venturi by a spring. The venturi
causes fluid flowing there through to substantially increase in velocity
and decrease in pressure relative to the liquid at the upstream end
thereof. Before the fluid level in the container reaches the lower end of
the dispensing device, the pressures between the upstream and downstream
ends of the venturi are equalized by outside air flowing into the movable
tube from the lower end of the dispensing device. When the fluid level in
the container reaches the lower end of the dispensing device, air can no
longer enter the movable tube to equalize the pressure. The low pressure
of the fluid jet draws the movable tube away from the venturi. The spring
loaded ball is pulled against the venturi, and fluid flow is shut off.
However, the movable tube cannot slide smoothly because it is only guided
at the upstream end by the venturi. The downstream end would wobble in the
jet and cause the upstream end to stick to the venturi. The valve is
relatively long, so that it can fit a limited variety of dispensing
devices. Also, the single venturi limits flow rate to a relatively low
level.
OBJECTS OF THE INVENTION
Accordingly, objects of the present automatic shutoff valve are:
to be compact and easily installed in a variety of fluid dispensing
devices;
to remain open when the fluid level in a container being filled is below a
predetermined level;
to automatically close and shut off the dispensing device when the fluid
level reaches the predetermined level;
to operate smoothly and reliably; and
to be very simple to produce.
Further objects of the present invention will become apparent from a
consideration of the drawings and ensuing description.
BRIEF SUMMARY OF THE INVENTION
The present fluid level controlled automatic shutoff valve is comprised of
a tubular housing with an axial bore which has an upstream closure, a
downstream opening, and an annular piston seat at the downstream opening.
A movable piston is positioned in the bore, and biased to a retracted
position by a tension spring connected between the piston and the closure
of the bore. A plurality of channels on the wall of the housing extend
between an upstream end of the housing and the bore. The channels
terminate in venturis downstream of the piston in the retracted position.
The shutoff valve is positioned in a fluid dispensing device. When
pressurized fluid is delivered through the dispensing device, the fluid is
directed through the channels and out the venturis at high speed and low
pressure. Before the fluid level in a container being filled reaches an
open lower end of the dispensing device, the pressures between the
upstream and downstream ends of the piston are balanced by air flowing
into downstream opening of the bore from the open lower end of the
dispensing device. When the fluid level reaches the open lower end of the
dispensing device, the air flow is cut off, and the low pressure fluid
from the venturis pulls the piston into the seat at the downstream opening
of the bore. Fluid flow is shut off.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a side view of the present automatic shutoff valve installed in a
fluid dispensing device, which is filling a container to an initial level.
FIG. 2 is a side sectional view of the shutoff valve, taken along a
vertical plane along an axis of the dispensing device, when a fluid level
in the container is as shown in FIG. 1.
FIG. 3 is an end sectional view of the shutoff valve, taken along line 3--3
in FIG. 1.
FIG. 4 is a side view of the fluid dispensing device and the container when
the fluid level reaches a lower end of the dispensing device.
FIG. 5 is a side sectional view of the shutoff valve when the fluid level
in the container is as shown in FIG. 4, and the shutoff valve is closed.
FIG. 6 is a side view of the fluid dispensing device when a trigger thereof
is released.
FIG. 7 is a side sectional view of the shutoff valve returning to an open
position after the trigger on the fluid dispensing device is released.
DRAWING REFERENCE NUMERALS
10. Automatic Shutoff Valve 11. Fluid Dispensing Device
12. Bore 13. Upstream Closure
14. Downstream Opening 15. Valve Seat
16. Piston 17. Spring
18. Drain Hole 19. Upstream End
20. Downstream End 21. Channels
22. Upstream End 23. Venturis
24. Container 25. Trigger
26. Open Lower End 30. Housing
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-3:
A preferred embodiment of the present fluid level controlled automatic
shutoff valve 10 is shown in FIG. 1 installed in-line in a fluid
dispensing device 11.
As shown in FIG. 2, shutoff valve 10 is comprised of a compact tubular
housing 30 with an axial bore 12 which has an upstream closure 13, a
downstream opening 14, and an annular piston seat 15 at downstream opening
14. A movable piston 16 is positioned in bore 12, and biased to a
retracted position by a tension spring 17 connected between piston 16 and
upstream closure 13. A small drain hole 18 extends between an upstream end
19 and a downstream end 20 of piston 16. A plurality of channels 21 extend
longitudinally along an outer wall of housing 30 from an upstream end 22
of housing 30. Channels 21 terminate in venturis 23 downstream of
retracted piston 16. Venturis 23 are angled inwardly into bore 12.
Channels 21 are also shown in an end sectional view of shutoff valve 10 in
FIG. 3. Alternatively, more or fewer channels 21 and venturis 23 may be
provided.
In FIG. 1, a pressurized fluid F is delivered through dispensing device 11
into a container 24 by manually operating a valve or trigger 25 thereon.
Container 24 has a fluid level L in FIG. 1. FIG. 2 shows the state of
shutoff valve 10 corresponding to fluid level L in FIG. 1. Fluid F is
directed at high speed and low pressure through venturis 23 into bore 12
downstream of piston 16, and out of downstream opening 14. Before fluid
level L in container 24 reaches an open lower end 26 of dispensing device
11, the pressures between the upstream and downstream ends of piston 16
are balanced by air A flowing into downstream opening 14 of bore 12 from
open lower end 26 of dispensing device 11. Piston 16 is kept in the
retracted position by spring 17.
FIGS. 4-5:
In FIG. 4, when fluid level L reaches open lower end 26 of dispensing
device 11, air flow into open lower end 26 is cut off. FIG. 5 shows the
state of shutoff valve 10 corresponding to fluid level L in FIG. 4. In
FIG. 5, the pressure at downstream end 20 of piston 16 is no longer
balanced by outside air. The high speed, low pressure fluid F from
venturis 23 pulls piston 16 into seat 15 at downstream opening 14 of bore
12 to shut off fluid flow and stop fluid level L at a predetermined point.
Valve or trigger 25 is released to shut off dispensing device 11. Fluid F
remaining in bore 12 is drained through drain hole 18 in piston 16.
FIGS. 6-7:
In FIG. 6, valve or trigger 25 is released and dispensing device 11 is shut
off. When enough fluid is drained through drain hole 18 and fluid pressure
upstream of piston 16 is relieved, piston 16 is biased by spring 17 back
into the retraced position, as shown in FIG. 7. Dispensing device 11 is
ready to be used again for filling another container.
SUMMARY AND SCOPE
Accordingly, the present automatic shutoff valve is compact and easily
installed in a variety of fluid dispensing devices. It remains open when
the fluid level in a container is below a predetermined level. It
automatically closes and shuts off the dispensing device when the fluid
level reaches the predetermined level in the container. It operates
smoothly and reliably. It is also very simple to produce.
Although the above description is specific, it should not be considered as
a limitation on the scope of the invention, but only as an example of the
preferred embodiment. Many variations are possible within the teachings of
the invention. For example, several shutoff valves can be connected in
parallel for filling multiple containers simultaneously. Closure 13 may be
integral to housing 30. A single channel 21 may extend completely around
the outer wall of housing 30, i.e., housing 30 may have a larger diameter
downstream portion and a smaller diameter upstream portion, so that the
upstream portion is spaced from the interior of fluid dispensing device 11
to form an annular channel. Instead of tension spring 17, a compression
spring may be positioned upstream of piston 16. Yet another type of spring
may be used. Therefore, the scope of the invention should be determined by
the appended claims and their legal equivalents, not by the examples
given.
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